U.S. Pat. No. 7,033,171 to Wilkerson discloses, as set forth in the abstract thereof, the following: “[a] molar tube having a first face portion that is adapted to be adhered to a molar tooth, a second face portion, and a mesial-distal length dimension. There is a body portion disposed on the second face portion of the base portion, and the body portion comprises an upper portion and a lower portion. The body portion further comprises a lumen that is adapted to receive an archwire, wherein the lumen has an axis which substantially coincides with the mesial-distal length dimension of the base portion. The body portion further comprises a boss comprising a threaded bore that is adapted to receive a setscrew, wherein the threaded bore has an axis. The axis of the threaded bore intersects with the mesial-distal length dimension to form an angle of any degree between 15 degrees and 55 degrees, including every degree therebetween. A molar tube according to the invention allows for easy adjustment of the tension in an archwire used in an orthodontic dental treatment, and provides for the painless withdrawal of the archwire at any time during or following the treatment.” Easy adjustment of the tension as referred to in the '033 patent to Wilkerson requires that the set screw be tightened while tension is applied to the archwire by the orthodontist. Further, in the '033 patent to Wilkerson, no mention is made of measuring the tension in the archwire.
Orthodontics is the specialty of dentistry which focuses on the diagnosis, treatment planning, and treatment of dento-alveolar and skeletal malocclusions. In layman's terms orthodontics broadly and nonspecifically refers to straightening and positioning teeth for the health, comfort, safety and appearance of the patient.
The two major components of fixed orthodontic therapy are tooth attachment mechanisms and archwires. Brackets and bands are used as attachment mechanisms. A band or a bracket may be attached to a tooth, either by cementing or bonding mediums. The purpose of the band or the bracket is to permit the health care provider to transfer a load or force to a tooth or to a group of teeth in order to elicit orthodontic movement of the selected tooth or teeth.
Two issues of concern in orthodontics are friction and management of forces. Although friction may have a positive effect in some instances it is usually associated with detrimental effects. The reason for this is that force which exceeds the ideal force necessary to move a tooth or teeth often must be employed to overcome various forms of friction which are inherent in the biomechanics of sliding mechanics. Thus, the tendency is for sliding mechanics to tax anchorage units (cause undesirable movement of a tooth or teeth that are used in the process of applying forces to a tooth or teeth for which movement is desired).
By contrast, another form of orthodontic biomechanics is referred to as looped mechanics. The “looped” in looped mechanics refers to a variety of shapes of loops which are built into and are an integral part of the archwire when it is constructed. The archwire is passive until the loops are activated. The activated loops act as springs in that they distribute a load through the orthodontic appliances to the tooth or teeth equal to the load of activation.
The load of activation is external to the patient's orthodontic system. Therefore anchorage is not compromised due to friction which is generated when sliding mechanics' techniques are employed for the movement of teeth. Frictional resistance is offset with forces external to the closed orthodontic system without additional energy costs to the closed system.
Orthodontists apply archwires and brackets as follows. First, brackets are attached on one or more teeth. Then the archwire is inserted into the brackets including the molar bracket tubes. The archwire is then ligated to one or more of the brackets. Force (tension) is then applied to the archwire which then opens (activates) or otherwise changes the spring dimensionally which is formed in the archwire. Opening of the spring is also referred to herein as activating the loop spring.
Tension is then applied to the archwire to activate a loop spring.
While forcing the archwire into and through the lumen or passageway of the bracket the orthodontist makes an approximation or educated guess based on experience as to whether or not enough force has been applied to the archwire so as to properly treat the patient. The archwire is then secured by bending it over the rear edge of the bracket to lock it in place.
At least two problems occur with this treatment structure and methodology. First, the locking which takes place by bending the archwire about the end of the bracket may become loose or disengage which then requires readjustment, re-locking or replacement of the archwire. Second, the amount of tension (force) effectively applied to the tooth or teeth is not known. Therefore, more visits to the orthodontist for adjustment and replacement are necessary. Additional visits to the orthodontist using present procedures is costly, inefficient and in some cases creates discomfort for the patient.
Therefore, it is highly desirable for an orthodontist to accurately know the force applied to a tooth or set of teeth. It is further highly desirable for an orthodontist to securely lock the archwire in place and at the same time achieve the desired tension (force). It is further highly desirable to enable the performance of clinical studies wherein the results of the application of a known force can be observed and recorded to assist in future treatment and diagnosis of patients.